Apparatus for lapping and polishing operations



Jan. 26, 1943. F. F. HILLDZ 2,309,588

APPARATUS FOR LAPPING AND POLISHING OPERATIONS Filed May 18, 1938 ll Sheets-Sheet 1 Jan. 26, 1943. 1 F. F. HlLLlX 2,309,588

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APPARATUS FOR LAPPING AND POLISHING OPERATIONS Jan. 26, 1943.

Filed May 18, 1938 11 Sheets-Sheet 3 17506 12502: 5 fbsrse f7 H/LL/X, fi 4mm F. F. HILLIX Jan. 26, 1943.

APPARATUS FOR LAPPING AND POLISHING OPERATIONS Filed May 18, 1938 ll Sheets-Sheet 4 [mania]:-

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F. F. HILLIX APPARATUS FOR LAPPING AND POLISHING OPERATIONS 11 Sheets-Sheet 8 Filed May 18, 1958 1760826307? FOSTER HALL/X,

F. F. HILLIX Jan. 26, 1943.

APPARATUS FOR LAPPI NG AND POLISHING OPERATIONS Filed May 18, 1958 11 Sheets-Sheet 9 QME R.

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APPARATUS FOR LAPPING AND POLISHING OPERATIONS Filed May 18, 1938 ll Sheets-Sheet l1 f A 4 #5 44am Patented Jan. 26, 1943 APPARATUS FOR LAPPING AND POLISHING OPERATIONS Foster F. Hillix, Lakewood, Ohio," assignor to The American Steel and Wire Company of New Jersey, a corporation of New Jersey Application May 18, 1938, Serial No. 208,661

9 Claims.

This invention relates to the production of substantially perfectly smooth surfaces, and, more particularly, relate to the production of mirror finishes on hard objects, such as, steel metal-working rolls, glass, etc. to work-pieces, it was obviously concluded that, if Although the inventive teachings that are to the surface defects of the rolls could be obviated, follow will find application in many fields wherethe surface characteristics of the stock rolled in highly polished, mirror-like surfaces are therethrough should show an improvement to a necessary or desirable, they specifically are dicorresponding degree. rected to that art of finishing metal-working The present invention had its inception in rolls, particularly cold metal-working rolls, the answer to the problem of how to improve the wherein the surface characteristics of the latter surface of metal-working rolls, and how to attain are reproduced in complement to an infinitesias nearly a true mirror finish as practicable mal degree upon the surface of the work-piece. thereon. However, though so directed, it is not intended Roll grinding and polishing practices in the that the invention shall be limited to the parpast have been productive of surfaces that apticular field of finishing metal-working rolls, as pear to the naked eye to be perfectly smooth. will become apparent after the claims appended Closer inspection reveals, however, that such hereto have been considered. surfaces, far from being smooth, possess very There are instances in the manufacture of definite imperfections, usually conforming to ro ed me a products, d pa t a in p odsome pattern, as scratches running circumferucts thiat 311:6 tout: subsenliigfizl glptlgged, it; infill; 1elilitially of thlileal roll, which further recourse to case 0 c omi or a co ro e e conventio grinding and polishing operastrip steel, wherethe perfection of finish on the tions fails to eliminate, and quitefrequently agsurface of the work falls far short of actual regravates, quirements. Plated objects, due to the lustrous t is necessary t have an understanding of mirror-like finish usually sought, ar pro e to the conditions and reasons underlying the disma nify every defect in the surface of the unadvantageous results obtained from conventional derlying metal to the extent that those minute polishing and g i di before clear under. imperfections. P 8 unnoticed the naked standing and appreciation may be had of that 9576/ the surface of the P metal, become which is to follow. For this reason a few words quite noticeable defects after plating. e a will be said in explanation of previous methods, of this, many otherwise sound pieces of plated leading up to a mmpaflson with the methods stock, or stock to be plated, must be rejected, herein fte set f th magigguction costs are thereby ob ectionably As is well known to the polishing industry. e For these reasons, it has, in the past, been 22 353 1 2 no g fig; 2 22 2: casual c comcustomary to prepare the surface of work-pieces posed of m microsco m hum d h n for plating, after the rolling and processing steps It is th m p ps an o e job of one seeking to make as smooth are done, by polishing, whereby the more obvious 4o and level a surface as possible (a perfect surdefects are eliminated, and the work pieces f bl for h 1 tam such ushi ace being hereinbefore and hereinafter repremade suita e t e pa po ng operations require extra time, labor materials sented as a true mirror to remove the humps and equipment and although the rejection scrap relative to the hollows, whereby a level condition is minimized thereby, the production costs are i g g sz g g r t: in

im ed. 1 Ore 890 case e um 1 32332335 gg z that u f imper into the hollows, and removing the excess, fections on the rolled metal work-pieces come, thus arriving at 8 f e that represents for the most part, from the surface of the rolls a mean level of all mp and hollows; or, (2) through which they have passed. 'The minute so By cutting away the humps until the entire 5hr. irregularities in the for of je ti n and face is at the level of the bottoms of the hollows. declivlties that constitute the surface contours The former o hese methods is known as burof the roll surface are reproduced in reverse or 118" n is nh r n n s ntially all complementary relief upon the surface of the rinding and polishing operations, as will later work-pieces. An unsatisfactory finish results appear, and the latter, though possibly loosely which necessitates further treatment of the work-pieces, as has already been indicated. In view of the thoroughness and fidelity with which surface characteristics are transferred from rolls known as a variation of polishing, is technically called, and properly known as lapping.

The difierences characterizing polishing and lapping are not only those reflected in their respective results, but are also those of instrumentalities and procedure.

Polishing may be said to be a refined form of grinding in that it is carried out, as in the case of the latter, with an abrasive wheel that is rapidly rotated and held against, and traversed across, the surface to be treated with consider able pressure. The abrasive grain is charged into the periphery of the wheel and held or fixed there by a suitable binder, and the grain size is relatively coarse; i. e., of a size to pass a screen having 600 meshes per square inch. On any surface that is of greater curvature than the wheels cicumference, or one that is fiat or convex, the contact between the wheel and the work is substantially linear, and the travel of the wheel-across the work is usually such as to introduce its cutting action in one direction, whereby all cuts made by the wheel are substantially parallel. Particularly is this true in the case of be gained by repeated polishing.

a cylindrical surface, which must be rotated past the wheel to present all of its surface thereto. Thus, .a rolling mill roll, when polished conventionally, will be found to have a surface with cuts running generally circumferentially, and, as it is said, with the grain laid down in one direction about the roll. Such a surface marking is called pattern, and, in this case, the pattern is that which is characeristic of polishing.

Further application of the polishing wheel to improve the surface, causes the fixed grain to track into the cuts formerly made by it, whereby the bottoms are dug deeper and the surface irregularities are aggravated. Accompanying this action there follows the burnishing action referred to hereinbefore, wherein the high points of the humps are forged over into the hollows at least partially to fill .thesame. Though this affords a surface that even under. close inspection appears to be fairly smooth, it, in fact, is an artificial and weak surface, which, under the application of working pressures incident to the rolling of metal, caves in or breaks down and becomes worse than if theadditional polishing and bumishing had not been resorted to.

Because polishing requires that the wheel be applied to the work-surface under considerable pressure, difficulty is encountered in relatively large particles tearing from the work or cracking loose from the wheel, which, upon coming into the zone of the work, cause gouges' or grooves in the work-surface, and thereby create "new bottoms down to which the entire surface mustbe averaged before a good polishing job may be had. This difiiculty is commonly referred to as the development of wild grains and constitutes one of the most troublesome factors in polishing operations.

Another difliculty that is quite prevalent in conventional polishing operations is that arising from the line contact between the polishing wheel and the work-surface when combined with the polishing pressures and periodic motion incident to the mechanical movements of the polishing operation. These factors combine to cause the polishing wheel to get out of round, which results in chatter marks" being developed on thesurface of the work. Before such marks can be eliminated by further polishing, the conditions are usually such as to cause the formation of other marks, which marks, in themselves, constitute one of the factors contributing to the periodic vibration of the machine, and which cause an aggravation of the condition rather than a correction thereof.

It will be seen from the foregoing paragraphs that there are several undesirable features in conventional polishing operations which stand in the way of attaining mirror-like surfaces by this method. The line contact and the unidirectional cut, while removing material from the high points ,of the surface, do not preclude the bottoms or valleys from being out still deeper, and the ultimate result is that very little is to The wild grain which develops from the pressures necessary in the polishing operation cause scratches of a greater magnitude than those provided by the regularly sized abrasive, requiring much additiona1 work to eliminate the damage thus done. The polishing wheel's becoming lop-sided is responsible for the formation of chatter marks and this difficulty can scarcely be circumvented without departing from the principles and instrumentalities of polishing. The grain becomes dull and tends to forge over the surface humps rather than to cut them away, and this, for the most part, causes a surface having much of the metal thereof in anunsupported condition, which caves-in upon being subjected to working pressures. In short, it may be said that the conditions in any polishing operation are as ideal as they can be made only at the beginning of the operation, and that all of the changes that must necessarily take place as the operation progresses are changes for the worse, and the general method and work done degenerates from perfection rather than coming nearer work progresses.

Although, it is possible to grind and polish surfaces to an accuracy well within one-thousandth of an inch-sometimes ten-thousandthsto perfection as the true mirror surfaces are much more accurate than this. Hence, mirror-like surfaces in the prior art have been attained, not by resorting to polishing operations, but, rather, by utilizing the manual system known as lapping, which is based upon the elimination of most of the undesirable factors discussed above. Inasmuch; as it is essential to obviate line contact and uhidirectional cuts on the work-surface, lapping is accomplished by employing a block that presents a substantial area of contact to the work, which may be moved in any direction so as to traverse the work-surface at any desired angle. 5

In conjunction with such a block,iit has heretofore been customary that fine abrafsive be fixed to the working face thereof; i. e., abrasive, the fines of which grade down to a size equivalent to that which will remain suspendedlin still water from 200 to 600 minutes, and even longer. These instrumentalities permit the use of relatively light working pressures, whereby cracking and spalling of the block, and the formation of wild grain incident thereto, is partially done away with. The grain size, being substantially smaller, has the advantage of affording a cleaner out and of remaining in sharp condition longer than the coarser sized abrasives employed in polishin whereby burnishing is eliminaed practically altogether. a

From these factors, a mirror-like surface may be closely approached by virtue of the fact that the lapping-block rides upon the tops of the humps on the work surface, and the grain size is insufficient to penetrate to the bottoms of the hollows to cause the routing action referred to scoring resulted. But the answer was found to in polishing operations. The motion imparted to .the block is such as will afford crossing previous cuts at a substantial angularity whereby the tendency for the grain to track in the previous cuts and make new bottoms, is nearly obviated. Furthermore, the lapping-block, instead of becoming out of conformance with the work surface,

as is the case in polishing when the wheel gets out of round, becomes more adapted thereto as the work progresses, whereby chatter marks" and other similar objectionable patterns rarely arise. The net result is that the humps of the work-surface are completely leveled off to a common bottom, beneath which only sound metal lies, and the evils of cave-in, usually growing from burnishing operations, are non-existent.

In so far as metal-working rolls are concerned, there are, among many others, three good reasons for providing as nearly a perfect surface thereon as possible, some of which have been touchedupon hereinbefore. These are:

1. The accuracy of finish of the roll surface is reproduced in the same degree upon the surface of stock rolled therethrough.

2. Rolling mill rolls so treated may be used from to 100 times longer before refinishing becomes necessary. This means that the cost of the operation is absorbed and the entire method is rendered economically feasible.

3. Roll surfaces of this kind are not affected by stock rolled therethrough so that the streaking eifect usually encountered upon conventional roll surfaces (which is defined by the circumferential points at which the edges of the stock come in contact with the roll) is practically eliminated. This means that, whereas formerly metal stock; such as strip, hadto be rolled in a definite order, commencing with the widest stock and finishing with the narrowest stock, to avoid streaking, the lapped surfaces on the rolls provide that stock may be rolled indiscriminately of width. whereby production schedules are more readily adaptable thereto.

The above reasons have been the cause of many attempts toprovide suitable methods of lapping ona commercial scale. Heretofore, lapping operations have been accomplished only by painstakingly slow manual'work, and have been unsuited to such commercial adaptation. Attempts to provide automatic means for lapping have failed to be successful in view of the extreme sensitivity of the procedure, and the necessity for such refinement of control, and total absence of extraneous motion and pressures, as may only be had from the delicate manipulation of a skilled artisan in this field.

Moreover, before an automatic, commercial adoption of lappi g could be achieved, still other obstacles remained to be surmounted. It was discovered that. even in the case of lapping, there was still some prevalence of wild grains; i. e., particles would still cut and bunch from the work-surface, or break from the block, and gouge out the surface to such an extent that hours of additional work would be required to bring the work down to the new bottom thus formed. One of the age-old tenets of the art of lapping stood directly in the path of solving these difliculties. The use of fixed grain has heretofore been considered axiomatic in this art, so necessary was it thought to be in view of the diiliculties attendant upon the use of loose grain. Loose grain was avoided because of control diificulties, which included the absence of means to feed it properly lo the zone of work whereby scratching and lie in the use of loose' grain, taken in coniimction with blocks of the right size, shape, and hardness, and also in conjunction with a scavenger solution in the lubricant; a scavenger being an additive agent for lubricants which cleanses the work of cuttings and precludes worn abrasives.

The principal dimc'ulty encountered in perfect-.

ing the present invention remained the one of wild grains. Study proved that the prevalence of these. as is the case in polishing; was caused by disintegration of the blocks under operatin conditions, and by the seizure of surface particles to the block, which would tear loose and bunch with the cuttings to form the hard wild grains. Lubricants minimized the seizing, but failed to obviate bunching of the cuttings, or disintegration of the blocks.

These latter difliculties were-found to be directly attributable to the fixed abrasive grain. Far better operating conditions and results were obtained when loose abrasive grain was finally employed, but it was not until a suitable scavenging agent was added to the lubricant that wild grains (those arising from bunched cuttings) were totally eliminated. The scavenger reduces the affinity of the particles for each other; acts as a dispersant, and, aside from cleansing the work to prevent bunching and keeping the grain sharp, functions to keep the grain one particle thick between the block and work-surfaces.

The manner by which loose-grain was ultimately fed to contribute to the success of this invention, and the theories and principles believed to underlie the operations in accordance therewith, are fully set forth hereinafter under the caption The method.

Accordingly, the present invention has for its primary object the provision of methods and means for automatically producing mirror-like.

surfaces upon articles, and, particularly, it pertains to the provision of suchsurfaccs upon metal-working rolls. a

It is another object hereof to provide a method and apparatus for automatically lapping surfaces to a high degree of perfection. and to accomplish by mechanical means that which has heretofore been obtainable only through manual operations.

It is still another object to provide a method and apparatus for lapping that can provide a mirror-like finish upon hard surfaces with great rapidity and precision.

It is another object to provide an apparatus" and various instrumentalities associated therewith, capable of being controlled to an infinite degree of accuracy, and capable of being com- .pensated to obviate all extraneous movement and periodic vibration while supporting, moving, and acting upon a surface to be finished.

It is another object to provide a machine wherein all the previous difficulties encountered in lapping and polishing operations are eliminated, whereby a controlled and predetermined pattern is obtainable upon the surface of the work-piece.

Many other objects and advantages will become apparent hereinafter when the following description is considered in conjimction with the accompanying drawings, in which;

Figure 1 is a front elevational view of the apparatus of the invention;

Figure 2 is a plan view of the apparatus of Figure 1;

the line IV-IV Figure 6a is an enlarged, fragmentary sectional view taken along line VI VI, Figure 7;

Figure 'l is a sectional view on the line VII-V11 of Figure 6;

Figure 8 is an enlarged fragmentary elevational view of a detail, part of which is shown in section;

Figure 9 is a sectional view on the line IX-IX of Figure 8;

Figure 10 is an enlarged fragmentary elevational view of a detail, part of which is shown in section;

Figure 11 is an enlarged fragmentary elevational view showing another detail;

Figure 12 is a view similar to that of Figure 7, but shows some additional elements of the apparatus of the invention;

Figure 13 is a sectional m1 of Figure 12;

Figure 14 is an elevational view of a detail, part of which is shown in section; and,

view on the line XIII- Figure 15 is a sectional view on the line XV- XV of Figure 14.

Referring now more particularly to the drawings in which like reference characters refer-to like parts throughout.

The general assembly, as is shown in Figures 1, 2 and 3, is carried within and supported by a housing 2, which composed of suitable plate sections secured together in any desired manner, as by welding, riveting, bolting, etc., and which are mounted upona bed or pedestal 3.

Inasmuch as the present apparatus is especially designed to treat cylindrical surfaces, such as metal-working rolls, special work-supporting means have been provided which will now be described.

Work support Referring more particularly to Figures 1, 2 and it will be seen that the top of the front of the housing 2 is closed by a coextensive, shallow pan member 4 within which are disposed two pairs of aligned spaced bearing members 5 50 arranged as to journal a pair of shafts 8 in spaced parallel relation to each other and to the long axis of the machine. These shafts are arranged for rotation within their respective bearings for purposes that will become apparent hereinafter.

The shafts 5 are arranged for simultaneous rotation to the same degree of arc, but in opposite directions, by means of gear seen in Figure 4. The gear trains include a pair of worm gears 8, respectively secured to the end of each of the shafts 6, which are arranged to receive rotative effort from a hand driven shaft l0, upon which is rigidly secured a pair of worms I! of reverse pitch, intergeared, respectively, with each of the worm gears 8.

with further reference will be seen that each of spaced relation a pair of sleeve members l3 which are slidably keyed thereto, as is shown at I4, for

to Figures 1, 2 ands, it

trains more clearly the shafts 6 carries in rotation therewith. integrally aflixed to each of the sleeves i3 is a pair of journal plates l5 of special configuration arranged to journal therebetween a series of rollers l6, l1 and IS. The disposition of the journal plates 15 is such as to place each roller in axial alignment with the corresponding roller of the assembly on the same shaft. This obtains in the case of the rollers on either shaft. It will also be seen by further reference to Figure 4 that the side plates carried by the sleeves of the adjacent shafts S are disposed to extend toward each other, whereby the axes of rotation of corresponding rollers among the four sets fall, respectively, within common horizontal planes. Thus, all rollers [6 have their axes of rotation in a common, horizontal plane; rollers ll havetheir axes in a different common plane, as do the rollers 18, and all of these planes are parallel. The adjacent edges of the side plates are speciallyformed, whereby the rollers may each be journaled adjacent thereto, with its periphery projecting a substantial distance therebeyond. It should be especially noted that this construction is such as to place each of the rollers in one assembly at a different radial distance from. the center of rotation of the shaft 6; one assembly being typical of all. All of the assemblies conform to this arrangement, whereby corresponding rollers fall atcorresponding, though opposed, positions upon each tical plane passing between the shafts 8 in a direction parallel thereto.

This construction has been described at length because of its importance in the proper supporting of a cylindrical body, such as a roll, since experience has indicated that there is probably but one feasible way by w ch this may be accomplished. The arrangement is such that the sleeves l3, side plates l5, and associated rollers l6, l1 and IB, constitute an adjustable cradle for engaging a cylindrical body, such as a roll,- adjacent each of its ends at points apart, and equally spaced on its circumference to each side of the vertical diametric plane of the body. Three rollers have been tentatively illustrated on each of the cradle elements, which, by virtue of their different distances from the axes of rotation of the shafts 6, may be raised or lowered, as the case may be, to support smaller or larger cylindrical bodies, whereby the center axis of each of the latter will fall close to the same horizontal line, and always in the same vertical plane. It will be understood that a; between opposite pairs of the cradle elements only two of the six rollers contact the cylindrical body at either end, and these are such as to afford points spmed circumferentially of the body at substantially 120, as has already been indicated. This means a four point bearing supports the roll.

It will be understood that a suitable hand crank 20 may be disposed on the end of the shaft l0, whereby the latter may be rotated to vary the disposition of the cradle elements, so that, if a large roll is to be accommodated, the uppermost rollers may be moved to a position to engage the roll at points 120 apart along its periphery. If a small roll is to be accommodated, the cradle elements are raised by turning the cranklll in the opposite direction, so that the lowermost rollers I! are in position to engage such a roll at points 120 apart on its periphery; it being understood that the rollers I8 are each journaled at equal distance from the axis of rotation of their respective shafts i, which distance is g eater than that of either of the other sets of side of the mid-verrollers I6 or I1. It will be further understood that the axis of rotation of each of the rollers may be employed upon each of the cradle elements in order that any number of differently sized rolls or cylindrical bodies may be accommodated. However, it has been found that the rollers of the cradle elements should provide the 120 relationship to any roll reposed therein in order that the latter will be afforded a maximum amount of lateral support without, at the same time, tending to wedge between the cradle elements and resist rotational effort. Furthermore, it is of importanc to note that this method of supporting the work accurately position the latter, whereby all adjustments and movements are eliminated except the one in vertical directions along the mid-vertical plane of the machine. The headstock to drive the work-piece, and the lapping devices for working thereon, are adjustable vertically to compensate for this want of adjustment of the work-support.

The work-support, just described, holds the work immediately above the pan 4, as may have been inferred from the previous description, whereby all sludge, cuttings, oil, etc., are intercepted, and held where they cannot interfere with the cleanliness and proper progress of the work.

Work rotating mechanism The work is adapted to be rotated as it reposes in the cradle elements, last described, by means of a chuck, headstock, and motor assem bly, which will now be described. Within the main housing 2, and as is indicated by broken lines in the lower left-hand corner of Figure l, is disposed a bracket member 23 arranged to support an elevating screw 24. 'Th screw is provided with a raising column 26 arranged to be actuated by operating shaft 25. The raising column 26 of the elevating screw 24 supports a pedestal 21 carrying an enlarged platform 28 at its upper end on which the headstock 29 for the chuck 48 (later to be described) is mounted.

The headstock assembly 29 includes a speed. reducer 3| having a drive shaft 38 disposed in axial parallelism with the work. The work is directly engaged by means of a chuck 48 which is connected to the shaft 38 by means of a universal joint, generally designated at 40. The universal joint, which is about to be described, is shown in greater detail in Figures 14 and 15.

The universal joint has been specially designed to afford a limited degree of universal movement without permitting any lost motion setting up between the driven and the driving elements, whereby the torque supplied by the latter is transmitted from the shaft 38 to the chuck 48 without loss. To the end of shaft 38 is-secured a T-shaped crosshead 42, the body of the T constituting a hub portion 4| adapted to be secured to the shaft 38. The opposite ends of the head of the T-shaped crosshead are provided with apertured bosses 43 adapted to accommodate bolts 45. Secured thereto by the bolts 45 is a circular disc 44, which is made fast with the former by means of nut 46.

The chuck 48 has secured to its face, adjacent the drive shaft 38, a disc 52, which is secured thereto by means of bolts 53, and spaced therefrom by washers 50. Thediscs 44 and 52 are jointed together by a coupling element 55, which is provided at its opposite ends with parallel cross members 56 and 51, respectively. The opposite ends of the cross member 56 are secured to the disc 44 by means of bolts and nuts 60 and 60a, respectively, which are disposed within apertures in the bosses 58 carried by the cross member 56, and through registering apertures located diametrically opposite each other adjacent the periphery of the disc 44, at points falling of are from the apertures accommodating the bolts 45 of the crosshead 42. The cross member 51 at the opposite end of the coupling member 55 is secured to the disc 52 on the chuck 48 by means of bosses 59, bolts 62, and nuts 63, in a manner, relative to the several parts thereof, similar to that already described in connection with the crosshead 42.

This arrangement is such as will permit a limited universal movement between the several parts by allowing the discs 44 and 52 to be flexed along their diameters falling parallel with the crosshead 42, and cross members 56 and 51, as well as along the diameter of the disc 52 through which the bolts 53 are passed. The discs 44 and 52, being preferably of a stiff material, such as steel, will allow such flexing in affording the universal movement, without, at the same time, permitting any lost motion to occur in transmitting the torque from the driving to the driven elements. The chuck 48 is secured to the end of the roll to be worked upon by conventional, automatically-centering clamps, and rotational effort is applied thereto through the universal joint assembly 40, last described, by means of the shaft 38, which is powered by means about to be described.

Referring once again to Figures 1, 2 and 3, it will be seen that the vertically adjustable platform 28 is extended to accommodate a motor 38 on the far side of the head stock from the universal joint 48. This motor may be of any design capable of infinite speed variation, and susceptible to accurate control and constancy of operation after being set at any given speed. Although any motor meeting these requirements may be employed, a fluid motor has been found to be particularly well adapted for this service. Accordingly, a fluid motor 38 has been indicated in the drawings, to the drive shaft of which is affixed a V-belt pulley 32 adapted to drive another V-belt pulley 34 upon a shaft of the speed reducer 3| by means of a V-belt 33. Inasmuch as it is desirable to effect the drive of the speed reducer with steady rotative effort, free from all vibration and extraneous movement, a fly wheel 35 is secured to the reducer shaft to which the pulley 34 is secured.

The work-piece, which has been illustrated as a rolling mill roll and designated by A in Figure 1, is disposed upon the cradle elements after the latter have been adjusted to afford the hearing upon the periphery thereof, previously described. Inasmuch as this may bring the rotational axis of the roll A slightly above or below the operating axes of the drive shaft 38, and associated elements 40 and 48, the elevating screw 24 is manipulated by means of the shaft 25 to bring'the platform 28, carrying the headstock, motor, chuck, and associated devices, into substantial axial alignment with the roll A. The chuck 48 is then made fast to the roll neck by means of the conventional centering clamps (not shown).

In order to determine that the drive shaft 38 patterns on the point 6Ia, which is adapted to engage or pass over the chuck 48 at some peripheral points on the latter. The relation of the lowermost portion of the gauge point 6Ia to the linear zenith of the circumference of the chuck determines the relative positions of the axis of the shaft 38 to the axis of the roll, or other work, A. Thus, when the horizontal plane, within which the path of movement of the extreme tip of the gauge point 6 Ia falls when oscillated, is exactly tangent to the periphery of the chuck 48 (this will necessarily be at the zenith of the periphery), the shaft 36, and the roll axis, as well as all intermediate parts, will be in substantially coaxial relation. Any slight inaccuracies remaining will be compensated for by the universal assembly 40, described above, and in addition, the latter will assure that the load under which the motor 30 is working will remain absolutely constant, and,

extraneous mechanical movement and vibration, or otherwise, in the machine.

The elimination of such periodic motion, and other extraneous movement, is highly essential due to the nature of the work being done, for reasons that have been mentioned hereinbefore, and which will be more clearly brought out hereinafter, because of the fact that all such motion would be reflected in the form of undesirable surface ofthe work.

'Traversing table As will latter appear, it is provided that the work-piece A will be traversed backwards and forwards by rapidly vibrating laps. To efiect this bodily traverse of the laps, the entire lapping head assembly is carried on a slidable table, which is constructed and arranged to move parallel'to the long axis of the machine, whereby relative movement, from one extremity of the work-surface to the other, between the latter and the laps may be achieved. The following is a description of the construction and operation of this table.

Referring to Figure 2, it will be seen that the upper portion of the housing 2, rearwardly of the closure pan 4, is provided at opposite ends of the machine with upstanding supports 65, providing pairs of aligned apertures in which a pair of stationary, parallel bars 66 is horizontally mounted. These bars 66 constitute a trackway upon which a slidable table 68, of inverted U- shaped cross section, as is more clearly seen in Figure 4, is adapted to ride. By further reference that, accordingly, there will be no period of II2 which support and close the ends of a longitudinally-disposed, elongated fluid-cylinder H3, which lies between the parallel horizontal bars 66 upon which the table is adapted to slide.

A stationary piston H5 is disposed within the fluid-cylinder H3 and carries a pair of oppositely extending pipes, as at H6 and Ill. These pipes H6 and H1 extend, respectively, through the left-hand and right-hand ends of the fluid cylinder and their bracket plates H2, and are elongated to extend through and project from aligned apertures H8 in cross-members which extend between the housings 65 at the ends of the frame 2 for supporting the parallel horizontal bars 66. Suitable packing is provided between the bracket plates II2 and the pipes H6 and III, as shown at I2I.

Each of the cross-members is vertically apertured, as at I22, right-angularly to intersect the aligned apertures IIB therein. Each end of the frame 2 is provided with a vertical screw-thread ed aperture I23 of reduced diameter which communicates with the vertical aperture I22 in the adjacent cross-member. Each of these vertical. screw-threaded apertures I23 is provided with an elongated screw I25, which extends into the vertical aperture I22 with which it communicates. Within each of the vertical apertures I22 in the cross-members there is disposed a slidable block I26, which rests upon the upper extremity of the elongated screw I25 that extends therein.

to Figure 4, it will beseen that the ends of the slidable table 68 are provided with two aligned pairs of inverted half-bearings 69, spaced in parallelism, each aligned pair of which is adapted to slide on one of the horizontal bars 66. Note should be made of the fact that the parallel bars 66, which form a trackway upon which the table rides, are purposely of round or cylindrical shape. This insures that oil appearing thereon will drip off, and thus constantly flush dirt and grit therefrom to maintain uninterruptedly, the free movement of the table at all times.

Referring to Figure 10, the slidable table 68 carries a pair of downwardly-depending, longitudinally-aligned, widely-spaced bracket plates This construction and arrangement of elements permits the adjustment of the longitudinal disposition of the piston H5 in the elongated fluidcylinder II3.

As will more fully later appear, the construction last described is such as will afford the necessary adjustment to determine the range of traverse of the slidable table, whereby a workpiece of peculiar shape (as an exceptionally longnecked roll) may be accommodated and properly worked upon. The particular piston-securing means described will not injure the external surface of the piston-pipes II6-I I1; this being of considerable importance in view of the fact that, at some positions of adjustment, the packing in the cylinders stuffing-boxes will pass over the points of the pipes II6-I H where formerly the clamp blocks and screws I25-I26 engaged them. If the external surface of each pipe is not smooth, trouble will be encountered in operating the slide table over different ranges.

The pipes II6-I I! are apertured adjacent their ends which are connected to the piston II5, as shown at I29 and I30, respectively. By

alternately introducing and exhausting fluid through these apertures, the cylinder H3 is forced to move to and fro, and since the cylinder is secured to the table 68, the latter is moved correspondingly along the horizontal bars 66. The adjustment, already mentioned above, of the piston I I5 relative to the stationary parts of the machine assembly will determine the range of movement of the table with respect to the transverse median line of the machine.

As will be seen when the operation of the table-reversing mechanism is discussed, the flexible couplings, whereby fluid pressure is introduced to-and exhausted from-the pipes I16- I II, are spared being moved backwards and forwards by the stationary piston-movable cylinder arrangement. This increases the life of the couphliinlgs and the operating efficiency of the ma- 0 e.

Table reversing mechanism Referring to Figures 8 and 9, the frame 2 carries a pair of longitudinally-aligned, widelyspaced bearings I35 in which there is slidably mounted a bar I 36 which lies alor gside the inner edge of the inverted U-shaped slidable carriage 68. Immediately below one end of the bar I36 there is disposed a pivoted bell-crank lever I38. On end of the bell-crank lever I38 extends upwardly, is bifurcated, as shown at I39, and provided with a transverse vertically extending elongated U-shaped slot I40 in each of the bifurcations. The adjacent end of the bar I36 is flattened, as shown at I M and extends between the bifurcated end I39 of the bell-crank lever I38.

The flattened end I of the bar I36 carries a transverse pin I42 which extends into the slots I40 in the bifurcations of the bifurcated end I39 of the bell-crank lever I38. The other end of the bell-crank lever I38 extends horizontally and pivotally carries a downwardly depending link I43, the lower end of which is pivotally'connected to the operating shaft I44 of a conventional two-way fluid reversing valve I45.

Each of the pipes H6 and H1 is provided on its outer extremity with a tubular cross-head I21. A pipe I28 is connected to each of the cross-heads I21 and extended through a suitable aperture in the adjacent end of the frame 2. Referring to Figure 3, the two-way reversing valve I45 is shown as provided with the pipe I48, which supplies the cylinder pipe H1; and a port I50 that is connected by a flexible tube II with the pipe I28, which supplies the cylinder pipe I I6. The two-way fluid reversing valve I45 is supplied with fluid through a port I53 by a flexible tube I54. 7

There is, of course, provided a relief port for the valve, whereby the exhaust fluid may be released and returned to the source of supply. This may be of conventional design, and no specific means for this purpose has been illustrated in the drawings.

The bar I36 is provided on its lower surface at any suitable point intermediate its ends with a pair of immediately adjacent V-shaped camnotches I56 having sharply inclined walls. Below these cam-notches I56 in the bar I36, the frame 2 is provided .with a vertically disposed tube I58 in alignment therewith. This tube I68 carries a cylindrical plug I59, the upper end of which is bevelled, as at I60, snugly to occupy either of the notches I56. The bottom of the cylindrical plug I59 carries a downwardlydepending shaft I6I, which extends through a. pipe plug I62 in the bottom of the tube I58. Between this pipe plug I62 and the'bottom' of the cylindrical plug I59, the tube I58-carries a coil spring I63, which is disposed exteriorly of the shaft I6I and tends to expand.

The bar I36 carries a longitudinally adjustable, but normally secured, arm I65 which is extended into close adjacency with the inverted U-shaped slidable carriage 68. Adjacent and facing the aim I65 on the bar I36 the inverted U-shaped slidable carriage 68 is provided with Within an elongated longitudinal T-slot I61. this slot I61 there is disposed a pair of stopmembers I69, which comprise T -headed bolts I having their shank portions extending outwardlv therefrom to receive a clamp-nut I1I.

As the slidable table 68 approaches the end of its movement in either direction, one of the stopmembers I69 in the elongated longitudinal slot I61 contacts and carries the arm I65 on the bar I36 with it for a very limited distance. The bar I36 is thus moved slightly, thereby displacing downwardly the bevelled plug I59 from which- 5 ever cam-notch I56 in the bar- I36 it happens at the time to be occupying. Since the bevelled cylindrical plug I59 will, in its normal position, re-

pose entirely within one of the notches I56 in the bar' I36 by virtue of the expansive force of 10 the coil spring I63, the reciprocative action of the bar I36 will be resisted until the apex of the bevelled plug I59 arrives at dead-center" positionwith the apex formed by and between the immediately adjacent notches I56 in the bar I36. 5 From the foregoing description it will be seen that, were the valve-operating shaft I 44 moved simultaneously with the initial movement of the axially-slidable bar I36 before the bevelled plug I59 had passed the dead-center between the g0 notches I56, the valve would be actuated to the half-way point as the plug came to dead-center position, and would thus close both the inlet and exhaust ports at each end of the valve. Obviously, the machine would stop, and become hung 5 in this position. To obviate this difliculty, the linkage somewhere between the slidable bar I36 and the valve operating shaft I44 is afiorded a suflicient amount of play, or lost-motion, to prevent the valve shaft I44 from being moved from its original position until the 'bevelled'plug I59 has passed beyond the dead-center point between the cam-notches I56. This may be conveniently accomplished by enlarging the clevis-pin holes in the bifurcated end of the valve operating shaft I44 axially of the latter the requisite amount. By this arrangement, the valve is actuated in a deferred-snap action movement familiar in the art of electric snap-switches.

Upon passing the dead-center position, the bevelled plug I59 is forcefully moved into the ad-' jacent notch I56 in the bar I36 by the expansive force of the coil spring I63 until the registration is completed. This action results in the extremely rapid movement of the bar I36 to its ultimate position. This rapid movement of the bar I 36 will, through the bell-crank lever I38, effect the deferred, substantially instantaneous movement of the operating shaft I44 of the two-way fluid reversing valve I45, whereby the energizing pressure of the fluid in the fluid-cylinder H3 is applied to one side of the piston H5, and relieved from the other, so rapidly that the retrogressive movement of the slidable table I68 is effected without any appreciable hesitancy, or dwell.

Lapping head mounting For reasons to become more apparent hereinafter, it is desirable to mount the lapping instrumentalities so that they may over-lie the work-piece. The principal reason for'this is to enable certain adjustments to be made, in some of which the force of gravity is utilized to attain the correct conditions. As will later appear, the lapping head is so mounted that, when the movemerit of the table, above described, is taken into consideration, together with the movement of the work-surface,- the resulting relative movements afforded between thelatter and the laps are, in

fact, universal ones. It has already been men-- 70 tioned that the lapping head mounting is carried by the slidable table 68. The precise constructional and functional details of this mounting will now be described.

Adjacent one end of the slidable table 68, there is secured an upstanding vertical post II, which is adapted to carry the lapping instrumentalities about to be described, and which may be better understood by reference to Figure 5. In this figure, it will be seen that a horizontally-extending, vertically-slidable supporting bracket I3 is carried by the vertical post II on the side of the latter adjacent the work-piece, or roll, A. To the inner end of this vertically-slidable support 13 is secured a lug I5, having a verticallyextending, internally screw-threaded bore therethrough, which extends within a vertically disposed slot 16 in the vertical post II to project interiorally thereof. The top of the vertical post 'II is provided with an aperture 14 to which the internally screw threaded bore of the lug I falls in axial alignment. Journaled within the aperture I4 is a depending elevating screw 11, the threading of which is complementary to the internal threading of the bore of the lug I5, and which extends through the latter to suspend it, and its associated support 13, upon the post H. The uppermost and outer end of the elevating screw shaft TI is provided with a bevel gear i8. which is adapted to mesh with a beveled gear 89 aiiixed to the inner end of a drive shaft 80, that is journaied within a tubular bearing I9, made fast to the vertical post II at right angles to the axis of the elevating screw ill. The outer end of this shaft 80 may be squared to accommodate a hand crank, similar to that shown in dotted lines at 83, in Figure 5, whereby in rotating the shaft 80 in either of two directions, the elevating screw Il may be rotated either to raise or lower the slidable support I3 carried by the post lI.

As has been mentioned hereinbefore, the slidable support I3 is arranged to carry the lapping instrumentalities. The sliding arrangement for this support is provided to compensate for the uneven wear' of the lapping-blocks transversely of the work-piece. This is accomplished by determining which side, and which of the two lapping-blocks, is getting the greater wear, and by either elevating or lowering the vertically slidable support I3 'to compensate for this different uneven wear. It will be seen that the raising and lower-ingot the supports 13 will operate to cant the supporting member of the lapping instrumentalities one way or the other relative to the work-piece. This will be more fully discussed when the operation of the machine is taken up.

'As will be seen in a detailed plan view in Figure 12, and as also shows in the more general view, Figures 1, 2, 3 and '7, the vertically-slidable support I3 has secured thereto a lateral tube 85 which extends in parallelism with the axis of the work piece A A rotatable shaft 81 is journaled in, and extends through, and projects from the lateral tube 85. One end of the rotatable shaft 81 extends through and projects from the vertically slidable support I3 and is suitably secured to one side of an angle-shaped member 89, on the other side of which the lapping head is carried, for reasons to become apparent hereinafter. The opposite end of the rotatable shaft 81 extends through and projects from the' outer end of the tube 85 and has secured to its extrem ity an S-shaped angle bracket I01 (see Figures 5b and 12). To the S-shaped angle bracket is secured, as by nuts and bolts I06, a balance beam 108, which extends at 90 to, andfor a substantial distance to each de of, the rotational axis of the shaft 81. The balance beam I08, adja cent its end overlying the work-piece A, is formed upwardly edgewise in the plane of its width to provide an ofl'set portion I08, in the end of which is journaled upon a horizontal axis a small sprocket I I0 adapted to be rotated by a counterbalanced hand crank III. The opposite end of the balance beam I08 is provided with an upstanding section II4 adjacent the upper extremity of which is journaled an idler sprocket I I0 in such a position that a line projected through its axis of rotation to the axis of rotation of the sprocket IIO falls parallel to the major axis of the balance beam I08. Tautly suspended between the sprockets I IIl-I I0 is a sprocket chain I I9, the explanation for which is immediately to follow.

Arranged to slide along the balance beam is a heavy beam weight I20, having bracket fixtures I24 secured thereto to which the opposite ends of the sprocket chain II9 are firmly secured by threaded hooks I3I and nuts I32 by means of which the sprocket chain is maintained taut.

By manipulating the hand crank III, the sprocket chain II9 may be actuated to slide the beam weight I20 in either direction along the balance beam I08. A calibrated scale rod I33 is secured to the weight for movement therewith, and extends parallel to the balance beam I08, across and beyond the offset portion thereof, to which it is secured for relative sliding movement by means of a shallow U-shaped retaining member I34. The scale rod I33 is calibrated to indicate the position of the weight I20 on the beam I08 relative to the point of fulcrum of the latter, so that the extent of declination, and amount of counterbalancing force necessary to repel such declination, of the balance beam may be read on the scale at the point where the rod I33 passes through the supporting member I34. This arrangement, as will be brought out more clearly hereinafter, i to determine and control the amount of pressures that the lapping-blocks exert upon the surface of the work.

The lapping head Returning now to the opposite end of the rotatable shaft 81, and to the angle member 89 through which the functions of the balance beam I08 and associated beam weight I20 are transmitted to the lapping instrumentalities, these latter are carried upon the other side of the angle member 89 by means of a lateral tube 90, extending in parallelism with the balance beam I08. The housing I90 is attached to the outer end of the lateral tube 90 at which point it is disposed directly to overlie the work-piece A. A rotatable shaft 9I is journaled within the lateral tube 90 and at one of its ends connects with a shaft in the housing I90, as will hereafter be described, and at the other of its ends projects through the angle member 89 to a point of termination closely adjacent the slidable support 13, and the vertical post .II. Upon this latter end of the shaft 9| is secured a belt pulley 93, which is suitably driven, as will hereafter be explained, to constitute the main drive for the lapping instrumentalities.

Referring now to Figures 6, '7 and 12, it will be seen that the housing I90 is secured to the lateral tube 90 by means of a tubular extension I9I having a flanged base portion secured to the housing by suitable fastenings; the extension being telescoped within the end of the tube 90. The arrangement of the lateral extension I9I on the housing I90, and its telescoping .relation housing I90 to be rotated relative to the lateral -the lapping-blocks, which adjustment is made possible by the construction last describedsuch undesirable patterns could be eliminated, and

fashion.

Referring particularly to Figure 7, the tool-vibrating mechanism housing I90 is shown as provided with a pair of bearings I93 which are aligned with the tubular lateral extension I9I and the rotatable shaft 9| in the tube 90. A crank shaft I95 is journaled in the bearings I93,

'and connected, as at I96, to the shaft 9|. The

throws I91-of the crank shaft I95 are'disposed intermediate the bearings I93. The ends of the housing I90 are provided with two pairs of bear--- ing members I99, each pair being aligned longithe work could thereafter be resumed in proper shafts 200.

tudinally of the housing and in spaced parallelism with respect to the other pair. Within each aligned pair of bearing members I99 there is mounted a reciprocable shaft 200; the construe-- tion and arrangement of shafts and bearing members being such that the-former extend be low and transversely of the crank shaft I95 at points which are between the throws I91 of the crank shaft I 95 and the bearings I93 thereof.

At one end of the housing I90 the reciprocable shafts 200 extend through and project therefrom, as shown at 20I.

The bearing members are provided with internal wear-resistant bushings 203, and suitable ex,- terior sealing members 204. The high grade bearings are necessary, in view of the great vibrating speeds (5000 revolutions a minute, or more) at which the lapping instrumentalities are operated, to obviate wear and extraneous'vibrations resulting therefrom. v

The absolute precision required by this type of work makes it imperative to have all parts going into the lapping head, and associated parts, weighed, constructed, arranged and balanced with extreme care. So much time and effort have been spent in reachingthe optimum in this regard, and so notable have been the results in minimizing, obviating, or absolutely controlling, all forces and motions surrounding this construction, that, when the mechanism is being normally operated at high speeds, such as that indicated above, an ordinary pencil, if stood on end atop the housing I90, will remain standing indefinitely, or until the operation is completed.

For the foregoing reasons, the cranks I91 of the shaft- I95, and all moving parts connected thereto, are arranged 180 apart in a 360 operating'cycle so that they will operate in opposite directions simultaneously, and will thus serve to be self-counterbalancing, rendering the entire assembly highly stable and devoid of irregular motion when operating.

Referring to Figures 12 and 13, each of the re ciprocableshafts 200 is provided with'a pair of parallel, upwardly-extending lugs 209, oneof which is enlarged, as at 20.1, on its upper extremity and carries a vertical stud 203. Each of the throws I91 of the crank shaft I95 carries a connecting rod 2I0 having its strap-end laterally offset, as shown at 2I2. The laterally offset lugs 203 on the reciprocable shafts 200 and are I connected thereto by wristpins 2 I 4.

'The vertical stud 208 on each of the shafts 200 carries a roller 2I5. A rectangular plate 2|], extending transversely of the housing I90, is bolted, as at 2I3, to the bearings I93 for the crank shaft I95. This rectangular plate 2I'I is provided with a pair of parallel elongated slots 2I9, one being disposed over the vertical studs 208 on each of the shafts 200. These parallel elongated slots 2I9 provide retainer guides for the rollers 2I5 on the vertical studs 208; whereby the twisting of the shafts 200 is prevented. It

should be noted that this construction is such as to place the rollers H5 and their bearing-slots 2I9 a substantial distance from the reciprocable This affords the greatest possible leverage for the securing and guiding means to hold the lapping-blocks in proper operating position, and has proved of great importance in precluding chatter.

The housing I90 is suitably gasketed and provided with lubricant.

Lapping block holders The projected ends 20I of the reciprocable shafts 200 are coniformly tapered, as shown at 220, and provided with cylindrical ends 22I of reduced diameter which are screw-threaded to receive nuts 222.

Referring to Figure 6, the numeral 225 desigthrough. Thus, each of the coniformly tapered portions 220 of the projected ends 20I of the reciprocable shafts 200 is constructed to receive one of the lapping-block-holders 225. It will readily be seen that the coniform taper '220 of the shafts 200 and the coniform apertures 228 in the lugs 22'! of the lapping-block holders 225 permit the rotation of the latter, whereby they may be adjusted for proper contact with rolls of varying diameters. In the case of very small rolls, two lapping-blocks are retained, rather than using one block, since the latter arrangement would throw the system out of balance.

Special lap-holders for small workto permit the use of the two blocks are, therefore, provided.

Thelap-holders shown in Figures 6, 6a and 7 have been especially designed to afford uniformity and smoothness of operation, and to preclude the lapping-blocks from jumping up and down because of any residual outlaw vibrations that might still issue from the machine. This is accomplished by utilizing live rubber under high compression to dampen and absorb extraneous movement.

' Referring more particularly to Figure 6a, the lapping-block L, which is of a particular design and material, later to be described, and which embodies the principles of construction disclosed inprior Patents Nos. 2,024,999 and 2,050,054, issued to me on December 17, 1935, and July 7,

, 1936, respectively, and in my copending application Serial No. 17,320, filed-April 19, 1995,a1l being entitled Lapping-blocks-is soldered into a channel-shaped clamp L This clamp is provided with two upstanding cups L which have an intumed flange L at their upper rims. A splash cap L is provided to close the cups L 

